TFAP2B and Patent ductus arteriosus: As yet, there is no substantial evidence linking TFAP2B to human eye disease; however, this gene is mutated in Char syndrome, a rare dominantly inherited condition that is associated with patent ductus arteriosus, facial dysmorphology and digit defects as well as sleep disorders (Gelb and Chung, 2014; Mani et al., 2005).